It is desirable to reduce the number of quartz crystals (XTAL) in an electronic system from various standpoints, such as, but not limited to, power consumption, reliability, space considerations, costs, etc. XTALs are used to generate electrical signals with accurate frequencies. As electronic systems get more complicated, demand for various and higher frequencies has increased. To satisfy this demand, phase locked loop (PLL) technology has been widely used. What PLL offers is to use a number of XTALs and generate almost any frequency out of reference signals based on the stable XTAL oscillators. Quartz XTAL oscillators however, have certain weakness. It has been very difficult and expensive to make very low phase noise oscillators at high frequencies above 100 MHz. This presents a problem.